Feature that displays a tooltip containing the time at the mouse position when hovering empty parts of the schedule.
ScheduleTooltip feature extends Tooltip and applies own logic to manage it.
It works as it should in bounds of feature goals.
If you need to have a tooltip attached to custom element with custom content, you need to implement your own based on docs I shared.
So the answer is - it doesn't work because it's not designed to be used like that.
Sorry if I didn't get your problem, I am not sure I follow this topic.
You asked about schedule tooltip feature and now the problem we are talking about is wrong calculation of durationInPx.